recommend an internal DAC project

[mlloyd1]

Well; I'm starting to look for an internally installable DAC for my old but very well built Onkyo DX5700 CD player. It's got lots of room, seperate supplies, various tweaks to the IV and filter circuits, etc.

But, I've never really done much with the digital part of the machine. Currently, it uses SM5813AP filter and a pair of PCM58 DACs. I thought about trying a project with a pair of PCM63K I bought a while back but never used (remember the old Elektor project? I've got the boards, too!). However, some of Burr Brown's newer DACs like the PCM1702 and PCM1704 look promising also.

Oh, before I forget, I will probably stick in a homebrewed Kwak Clock (what a great name!), JFET version, before I'm done, although Onkyo did a pretty good job with the clock in this machine.

So what do you folks recommend?
thanks!
mlloyd1

[guido]

Mmm,

The old elektor design has a 1 ohm resistor between dig and analog ground. Got an old application note from Analog Devices which says that is not the way AT ALL. (go it only on paper)

There is only one way: tie both grounds together and then off to analog ground. Otherwise the digital noise gets on the analog output (if i remember the piece correctly).

Now for the BB 94 data book and i quote the PCM63P datasheet:
Both commons should be connected to an ANALOG ground plane as close to the PCM63P as possible.

Also the design is using an YM3623B chip. The crystal CS8412 and CS8414 are better (i've heard). But in your case you maybe able to connect the dig filter directly to the players circuit.

Happy tweaking,

Guido

[Jocko Homo]

I have stuff in my junk box that fits your needs. Send me an email, and I'll give you details on what I have.


And AD is right........that is not the way to go.

The Yamaha part works just as well, even though Stereofool will tell you elsewise. Actually, it has some advantages.

Jocko.

[HarryHaller]

And what advantages would they be? In all honesty you do have to drive the Crystal at logic levels to get it to sound good. You also have to drive the Yamaha at logic levels to get it to work. The Crystals sounds better if you drive it diffential which is a simple CMOS logic circuit. The Yamaha should have the start up oscillator killed after it achieves lock for the best sound. The new Crystal receivers sound better than the CS8412s.... there are several types to chose from. Got a good interface circuit for between the digital input and the receiver chip Jocko?

H.H.

[Jocko Homo]

I wasn't talking to you, Hairy.

Yes, differential input is nice, but pointless if it uses a Schmitt trigger.

The cheap Yamaha won't reflect crud back to the input the way the Crystal does.

So........make a differential input circuit (details not to follow......I'll let Hairy do that) and use the Yamaha.

If you can find one.

I have lots surplus.

Jocko.

[HarryHaller]

Through it in the public domain and your fair game....... I agree that the Yamaha can be made to sound very good and good implementation of the digital interface is more important the choice of the Crystal or Yamaha receiver. Hell, you can even get digital cables with RCA plugs to sound great with a very simple network inside the RCA plug...... Right Jocko?

[Jocko Homo]

Well, you can, but why go to through the hassle?

[HarryHaller]

Repo men live for hassles. Why go the the hassle of any of this High End stuff. Then again, why not?

H.H.

http://www.anchorbayentertainment.co...t.asp?p=22&n=3

[tschrama]

Hi everybody ...

has anybbody taken a look atb the ad1862 should be in the same class as the PCM1702.... maybe you can considder this as an alternative.

Would it be difficult to make a DAC with a ad1862?


greetings,
Thijs

[Jocko Homo]

Easy to do it with them, just more expensive than PCM1702.

Email me if you have any questions.

Jocko